Thermogravimetric analysis of co-combustion between municipal sewage sludge and coal slime: Combustion characteristics, interaction and kinetics

Abstract

Based on the physical and chemical properties of municipal sewage sludge (SS) and coal slime (CS), the combustion behaviors of SS, CS and their blends were investigated by the thermogravimetric analyzer. The interaction between SS and CS was evaluated, and the combustion reaction rate equations were obtained. The results suggest that during the co-combustion, SS could improve the ignition performance, while CS could enhance the activity in the high temperature zone and improve the slagging characteristics. There was the most significant interaction in 550–600℃, which had a positive effect on the entire combustion process, and the synergy reached its peak when the CS ratio was 40% with synergy index SI=1.53. The combustion of the blend was a multi-step process, which conformed to the nth-order model, and the addition of CS could reduce the apparent activation energy of SS during the entire combustion process.